Chem Final Review

• Properties of carbohydrates

  • Size of base carbon chain
  • Location of the C=O functional group
  • Number of the sugar units
  • Stereochemistry of the compound
• General formula of a carbohydrate

  Cn(H2O)n where n can be any number
• For every carbon atom there are 2 hydrogen and 1 oxygen atom
• Ketones and aldehydes


  Need to be able to distinguish between them

  
• Carbohydrate chains


  • Trioses (3)
  • Pentoses (5)
  • Hexoses (6)
• Trioses


  • Glyceraldehyde: simple sugar that exists as a stereoisomer with an L and D formation, serves as an important starting material in both glycolysis and gluconeogenesis, and is a building block for larger sugars
  • Dihydroxacetone: A simple carbohydrate, similar too Glyceraldehyde, has a stereoisomer and is an intermediate product in glycolysis
• Pentoses


  Xylose: a simple sugar largely found in plant materials such as wood, straw, corn cobs, and small amounts can be found in fruits and vegetables
• Hexoses

  • Glucose
  • Fructose
• Haworth formula


  Hydroxyl group can exist below the plane of the ring (alpha) or above the plane of the ring (beta)
• Know the difference between D and L orientation in carbohydrate chains as well as the alpha and beta orientations referring to the Haworth formula. The Haworth nomenclature using a and B is like using D/L in fisher projections. They both refer to the positioning of the hydroxyl group on the same carbon.
• Monosaccharide


  Simplest form of a carbohydrate or simple sugar, or a single sugar molecule, one that is not bound or linked with others
• Oligosaccharides


  Disaccharides; series of simple sugars, multiple sugars that are bound together
• Oligosaccharides


  • maltose: 2 glucose molecules
  • lactose: 1 molecule galactose + 1 molecule glucose
  • sucrose: 1 molecule fructose + 1 molecule glucose
• Starch: Plants

  Amylose: long, unbranched chains of 25 – 300 glucose molecules linked by a- 1,4 glycosidic bond,

  Amylopectin: branched chains with >1000 glucose unit
• Glycogen: Animals

  More highly branched than amylopectin. In humans, this branching process occurs due to enzyme GBE or glycogen branching enzyme. Normally glucose rings will bind via the 1st position carbon in the ring and the 4th position carbon of another ring thanks to enzyme Glycogen synthase. This enzyme invites a binding between the 1st position carbon of one molecule and the 6th position of another. Leading to a branching affect.
• Insulin


  Produced in the Beta cells of the pancreases, promotes the decrease of blood glucose levels
• Glucagon


  Produced in the Alpha cells of the pancreases, promotes increase in blood glucose levels
• Be able to distinguish between the two glucose methods mentioned in class. More specifically refamiliarize yourself with the reactions as far as the enzymes used in the reactions and what the measured product is.

  
• Specimens for glucose testing


  • Plasma or serum
  • Whole blood: self monitoring glucose device (POCT)
  • CSF: Done to investigate potential between viral and bacterial infections
• Interfering substances for glucose testing


  • ascorbic acid
  • uric acid
• Types of glucose tests


  • Standard alone test: fasting or random
  • Basic metabolic panel
  • Comprehensive metabolic panel
  • Oral glucose tolerance test
• Reference intervals for glucose testing


  • Fasting glucose: 70-99 mg/dL
  • Random glucose: <200 mg/dL
  • 2 hr OGTT: <140 mg;dL
• Oral glucose tolerance test

  Purpose: represents one of the ADA diagnostic criteria for diabetes mellitus

  1. Patient preparation: Discontinue all medications & dietary supplements that affect glucose tolerance, if possible (biotin), Unrestricted diet & normal physical activity; fasting 8-10hrs minimum

  2. Obtain fasting glucose plasma: Results <140 mg/dL continue with OGTT, Results >140 mg/dL stop testing
• HbA1C testing


  Gives you a good indication on how well your diabetes is being controlled. When glucose is present in the bloodstream, it can bind to hemoglobin. This process occurs gradually over the lifespan of the RBC and can also occur in individuals that aren't diabetic. When analysis reveals elevations in the amount of glucose bound hemoglobin compared to non glucose bound hemoglobin, this becomes indicative of a metabolic disorder. Reflects glucose control over a period of 3 months, RI: 4.0 – 5.6%, Measurement methods: HPLC/immunoassay/ion-exchange chromatography
• Ketone testing in serum


  Testing for diabetic patient, used as a diagnostic and monitoring tool for diabetic ketoacidosis; Acetoacetate, Acetone, and B-hydroxybutyrate. When these ketone bodies form. B-hydroxybutyrate is usually formed in the highest concentration compared to the others. As such it makes it a target for analysis in lab testing,

  Method: B-hydroxybutyrate dehydrogenase,

  Interpretation: RI: < 0.4 mmol/L; elevated levels can be seen for a variety of reasons however, results that are >2 mmol/L are typically seen in patients experiencing DKA
• Ketone testing in urine


  In diabetic patient, diagnosis and monitoring of diabetic ketoacidosis. Must be refrigerated if testing is not performed within 1 hr; detection acetoacetate
• Pancreas


  Dual purpose organ, Functional unit: endocrine and exocrine, Hormones: Insulin (inhibits gluconeogenesis and stimulate glycogen formation; Increase glucose uptake by liver, skeletal muscle, adipose tissue), Glucagon (increased plasma glucose caused by stimulating glycogenolysis & gluconeogenesis), Proinsulin (inactive form of insulin, composed of the insulin molecule itself and a structural component called Connecting peptide or C-Peptide), Somatostatin (acts as a regulator for the other hormones; acts as an inhibitor for insulin, glucagon, and gastrin and growth hormone maintaining hormonal balance)
• Exocrine pancreas


  Acinus, where the acinar cells are that produce the bicarbonate and digestive juices
• Endocrine pancreas


  Islet of langerhans, cluster of cells in the middle that produce the hormones secreted into circulation
• The pancreas serves both exocrine and endocrine functions. Exocrine function involved secretion of enzymes and bicarbonate into the digestive tract. Enzymes aid in the digestion of carbohydrates , fats, and proteins. Bicarbonate help neutralize stomach acid. Endocrine function involves hormone secretion directly into bloodstream. Insulin and glucagon are key hormones involved in sugar level regulation.
• Type 1 diabetes


  Insulin deficiency: loss of pancreatic Beta cells, Glucose >300mg/dL, Ketone bodies > 5mM, Metabolic acidosis pH<7.3, Usually occurs before age 30, Not found in only juveniles anymore
• Type 2 diabetes


  Accounts for 90 – 95% of diagnosed cases, Relative insulin-deficiency, Not found in only adults anymore!, Non-obese (<10%), Defect in number / affinity of insulin receptors, Post-receptor responses, Obese (90 – 95%), Usual candidates for metabolic syndrome
• Type 1 diabetes Etiology

  • Hyperglycemia: elevated glucose levels
  • Polydipsia: excessive thirst
  • Polyuria: excessive urination
  • Glucosuria: excessive glucose found in urine
  • Ketoacidosis: lowering blood pH due to formation and presence of ketones
  • Ketonuria: excessive ketones found in urine
• Type 1 diabetes therapies


  • Insulin injection
• Type 2 diabetes Etiology

  • Hyperglycemia: elevated glucose levels
  • Polydipsia: excessive thirst
  • Polyuria: excessive urination
  • Glucosuria: excessive glucose found in urine
• Type 2 diabetes lab testing

  • HgbA1C
  • Fructosamine
• Type 2 diabetes therapies

  • Sulfonylureas
  • Biguanides
  • Thiazolidinediones (TZDs)
• Thyroid


  Function: influence on metabolic functions, thyroid hormone production, growth and sexual maturation in mammals,

  Functional unit: thyroid follicle,

  Localized around the trachea,

  Composed of to primary lobules on the left and right that are connected by a band of tissue referred to as the isthmus
• Parathyroid


  Function: regulation of calcium levels through PTH hormone,

  -maintaining bone health, -maintain balance of phosphorus levels. Located on the back side of the thyroid gland, There are for globular glands imbedded within the tissue of the thyroid gland itself (Superior (top 2), Inferior (bottom 2))
• Parafollicular Cells


  Similar but distinct cells within the thyroid, they are not located within the follicles but within the spaces around the follicles, These cells secrete calcitonin